Adobe InDesign is a document design software in the Creative Cloud lineup. It’s especially good for print documents, given the options with bleed, margins, color, and placement of elements. A similar program is Microsoft Publisher, which has a lower learning curve than InDesign does. 

InDesign has specific features that make it good for documents with many pages, but it can just as easily be used for a one-page project like a flyer. 
UIUC offers Adobe Creative Cloud for free for its students, which you can download from the Illinois Webstore. Staff and faculty have their own download link. It can take up to a day for Campus IT to activate your Adobe License, at which time you can download any of the Creative Cloud programs. There is a webpage with instructions on how to activate your access to Creative Cloud as well.